The present invention relates to a block inlaying puzzle in which a set of a plurality of blocks each having a plan configuration consisting of at least one basic shape is inlaid in a block inlaying recess having a planar bottom surface whose configuration consists of a plurality of the basic shapes.
A block inlaying puzzle of the kind referred to above is known from, for example, Japanese Patent Publication No. 47-7497. The puzzle employs a set of twelve blocks which are identical in area with each other, but are different in plan configuration from each other. Each block has a plan configuration in which six basic shapes that are regular triangles are assembled together. The twelve blocks are inlaid, without gap, in a block inlaying recess having a planar bottom surface of a specific configuration. The puzzle is monotonous and lacks fun because a restriction imposed on inlaying of the blocks in the block inlaying recess is only the configuration of the bottom surface of the block inlaying recess. In other words, there is a problem that once the configuration of each block and the configuration of the bottom surface of the block inlaying recess are determined, the degree of difficulty of the puzzle is determined.
Furthermore, a so-called checkerboard puzzle is also known, which employs a set of blocks. A plurality of squares that are the basic shapes are assembled together to form the blocks into various plan configurations. The alternating squares are different in color from each other. When the set of blocks is inlaid in a block inlaying recess, a checkered pattern is formed. The checkerboard puzzle is generally high in degree of difficulty, because of such a restriction that the blocks must be inlaid in the block inlaying recess so as to form the checkered pattern. However, the degree of difficulty of the checkerboard puzzle is determined, once the configurations of the respective blocks, the configuration of the checkered pattern and the configuration of the bottom surface of the block inlaying recess are determined.
An easy puzzle pattern is suitable in the degree of difficulty for a beginner, but is not suitable for an expert. On the other hand, a difficult puzzle patter is suitable in the degree of difficulty for the expert, but is not suitable of the beginner. Further, there is also such a problem that even if a player finds out a puzzle pattern suitable for himself in the degree of difficulty, he will soon get used to the puzzle pattern so that the puzzle pattern becomes easy for him, because the degree of difficulty is maintained unchanged. Thus, the puzzle pattern becomes monotonous for the player so that he will be tired of the puzzle.